A former top education ministry bureaucrat told a Diet committee meeting on Monday that the office of Prime Minister Shinzo Abe had significant influence over the government’s decision to approve a new department at a university run by his friend.

Abe’s aide was clearly involved in the approval process for the veterinary department at the Okayama University of Science in a government-designated special economic zone, said Kihei Maekawa, former vice-minister of the Ministry of Education, Culture, Sports, Science and Technology.

“The prime minister’s office worked behind the scenes,” he told the committee, which he attended as an unsworn witness called by opposition parties. The Cabinet Office, not the prime minister’s office, was responsible for dealing with issues related to special economic zones, he added

Kotaro Kake, chairman of Kake Educational Institution, which runs the university, is known as a close friend of the prime minister.

Appearing in the joint session of the House of Representatives’ cabinet affairs and education committees, Maekawa reiterated that the review process was “unclear” and “unfair”, citing insufficient discussion about whether Kake Educational Institution met conditions to launch Japan’s first vet school in half a century.

Abe has come under fire over suspicions he influenced the approval process for the opening of the new department at the university in Imabari, Ehime Prefecture, western Japan.

Such suspicions have grown after documents revealed that officials from the Cabinet Office pressured the education ministry ahead of the selection of Kake.

Maekawa has said he remembers having seen some of those documents while he was still working at the ministry.

The documents, which Maekawa insists are authentic, say officials employed phrases such as “what the highest level of the prime minister’s office has said” and “in line with the prime minister’s wishes”. Abe and other cabinet members have repeatedly denied wrongdoings.

He has drawn suspicion over his dubious ties with public school operator Moritomo Gakuen, which bought state-owned land in Osaka at a bargain price. Abe’s wife Akie was named honorary principal of the junior school that Moritomo planned to open at the site.

Maekawa resigned in January to take responsibility for a scandal in which the ministry systematically secured post-retirement jobs for its bureaucrats.